Process of making anthraquinone alpha disulfonic acids.



' ROBERT E. SCHMIDT,

FABRIKEN OF ELBERFELD 00., OF NEW UNITED STATES Patented November 3, 1903.

PATENT OFFICEJ OF NEW YORK.

OF ELBERFELD, GERMANY, ASSIGNOR TO FARBEN- YORK, N. Y., A CORPORATION SPECIFICATION formingpart of Letters Patent N0. 742,910, dated November 3, 1903. Application filed June 2'7, 1903. Serial No. 163,367. (No specimens.)

To all whom it may concern:

Be it known that 1, ROBERT E. SCHMIDT, doctor of philosophy, chemist, (assignor to the FARBENFABRIKEN or ELBERFELD 00M- PANY, of New York,) residing at Elberfeld, Germany, have invented a new and useful Improvement in Processes of Making Anthraquinone-Alpha-Disulfonic Acids; and I hereby declare the following to be a clear and exact description of my invention.

I have found a new process for the manu facture of the anthraquinone 1: 5 and 1: 8 disulfonic acids, which process consists in first treating anthraquinone or anthraquinone-alpha-sulfonic acid with fuming sulfuric acid in the presence of mercury or mercury compoundssuch as mercurous or mercuric salts, mercurous or mercuric oxid, dad-until a mixture of the two above-named disulfonic acids results and then separating these acids from each other.

In carrying out In y invention practically I can proceed as follows, the parts being by weight: A finely-powdered mixture of one hundred parts of anthraquinone and one part of mercurous sulfate is mixed with two hundred parts of fuming sulfuric acid (-14% S0 and the resulting mass is slowly heated. At about from to centigrade a reaction sets in. One must take care thatthe temperature does not exceed to centigrade. It is kept at this temperature until a test portion is soluble in water and until all sulfuric anhydrid may have totally or nearly disappeared. During the heating the 1: 5 anthra quinone-disulfonic acid separatesin the shape of quadratic plates. It is allowed to cool down to about 50 centigrade, the melt is mixedwith seventy-five parts of sulfuric acid, (66 Baum,)andthe1z5 anthraquinone-disulfonic acid is filtered off. It can be further purified by dissolving it in hot water and precipitatin g again in the shape of the potassium salt by the addition of potassium chlorid. Subsequently the filtered sulfuric-acid solu tion is run into water. The solution thus ob tained is heated, and from this hot solution the potassium salt of 1: 8 anthraquinone-disulfonic light-yellow needles by the addition of potassium chlorid.

Of course the separation of the two sulfonic acids can also be carried out by a fractional crystallization of their salts.

The resulting 1: 5 and 1:8 anthraquinonedisulfonic acids yield 1: 5 and 1:8 diamidoanthraquinone or 1:5 and 1:8 symmetrical dimethyldiamidoanthraquinone on being heated with ammonia or with monomethylamin.

Having now described my invention and in what manner the same is to be performed, what I claim as new, and desire to secure by Letters Patent, isv 1. The new process for the production of the 1: 5 and 1:8 anthraquinone '-disulfonic acids, which process consists in first treating anthraquinone with fuming sulfuric acid in the presence of mercury until the disulfonation is completed, and then separating the two acid is precipitated in the shape of I resulting disulfonic acids from each other,

substantially as described.

2. The newprocess for the production of the 1:5 and 1: S anthraquinone disulfonic acids, which process consists in first treating anthraquinonealpha-monosulfonicIacid with fuming sulfuric acid in the presence of mercury until the disulfonation is completed, and then separating the two resulting disulfonic acids from each other, substantially as described.

3. The new process for the production of the 1:5 and 1:8 anthraquinone-disulfonic acids, which process consists in first treating anthraquinone with fuming sulfuric acid in the presence of mercury compounds until the disulfonation is completed, and then separatiug the two resulting disulfonic acids from each other, substantially as described.

4. The new process for the production of the 1:5 and 1: 8 anthraquinone-disulfonic acids, which process consists in first treating anthraquinone-alpha-moncsulfonic acid with name in the presence of two subscribing wit= fuming sulfuric acid in the presence of mernesses. cury compounds until the disulfonation is completed, and then separating the two re- 5 sulting disulfonic acids from each other, sub- Witnesses:

stantially as described. OTTO KGNIG,

ROBERT E. SCHMIDT.

In testimony whereof I have signed my 1 J. A. RITTERSHAUS. 

